1. Field of the Invention
This invention relates to conduit cleaning systems, and especially to an electric and water-pressure powered, automatically-operable beer coil and conduit cleaner
2. Description of the Prior Art
The usual beverage delivery system comprises a source of the beverage, for example a keg of beer, a source of pressure, for example a container of compressed carbon dioxide, and a conduit to carry the beverage to a discharge point having a manually activated spigot. In order to discharge a beverage at an appropriate temperature for drinking, the beverage source may be stored in a temperature-controlled area, or the beverage-carrying tube may be passed through such an area, thereby bringing the beverage to desired temperature. In taverns, the system frequently takes the form of a refrigerated room for storage of kegs, and a system of permanent tubes or conduits for connecting the kegs to distribution spigots at a customer area.
Draft beer from the keg is an unpasteurized material which is surprisingly sensitive to rough handling. Discontinuities in pressure and temperature encountered by the beer may cause unacceptable foaming, and may adversely affect the taste and aroma. During brewing, the brewmaster, of course, has various means of controlling the chemical and physical environment of the processed materials. In order to ensure correct taste, aroma and appearance, similar care must be taken with the beverage delivery system.
In addition to the care which must be taken to maintain the optimum taste aroma and appearance, correct sanitation requires that the beverage delivery system be as clean as possible. Under some circumstances, the organic materials present in the beer may chemically react or decompose, and so-called beer stones may precipitate out in the conduit system. Unless the conduits are kept clean, microbial action can occur which degrades the beer.
The most frequently encountered beverage delivery systems in devices for heat exchanged delivery employ a heat transfer section along the beverage delivery conduit, which heat transfer section is located in a refrigerated area. The kegs may or may not also be kept refrigerated. Relatively warner beer from a keg is conveyed along a conduit to the heat transfer passage, immediately preceding the spigot. It will be appreciated that the heat transfer section, which normally takes the form of a helical coil of metal tubing, introduces both a physical discontinuity and a temperature discontinuity encountered by the beverage being conveyed through the conduit. Such systems therefore may be expected to cause foaming of the beer, and to produce variations in beverage treatment (e.g., variations in output temperature) as a function of the rate of discharge of beverage.
Beverage delivery systems employing heat transfer coils are also more susceptible to accumulations of unwanted materials than are simple conduit sections of systems in which the kegs themselves are stored in a temperature controlled area. Nevertheless, both types of beverage delivery systems must be regularly cleaned both to provide a good beverage and to comply with relevant health codes.
Conduits may be cleaned by flushing with cleaning fluid and water. Having added a cleaning fluid manually, early conduit cleaning systems employ water pressure to fill conduit systems with water, and then a manually-operated pump device to surge and agitate the cleaning solution within the conduit, thereby loosening foreign materials. The conduits are then opened and gravity drained. U.S. Pat. Nos. 1,993,371 Jones; 2,023,854 Petricone; and 2,078,740 Stahl involve such devices. In order to function, an agitation device of this kind must employ either a circular path around which the fluid is agitated, or a substantial length of conduit must be involved such that a surging flow can be accommodated in a closed section. The aforesaid patents to Jones and Petricone teach cleaning a pair of adjacent beverage delivery tubes at the same time by connecting them in a loop. In order to accomplish the connection, the beverage tubes are removed from their kegs and connected together at the keg storage area; and, the pump is connected between the distribution spigots at opposite end of the tubes being cleaned. A third connection to a source of water allows the flushing system to be charged with water, after which the user operates the pump to force the water around the circular passage created by the connection of conduits. The requirement of connection presents a danger of spillage which is a serious problem in a refrigerated storage area. Such connections likewise do not lend themselves to automatic operation.
The cleaning device of Stahl is somewhat more simple in that the manually-operated pump functions on a first stroke to draw cleaning fluid into the pump chamber, and in a second stroke to discharge the pump fluid into the beverage coil conduit. The fluid is alternately surged into the beverage coil and drawn back into the pump, finally being discharged into a reservoir. Unless the spigot is opened during cleaning, the flow is necessarily directed into a closed conduit, and substantial conduit length is necessary before appreciable surging of cleaning fluid will occur. Moreover, in such system, the surging will occur only in a portion of the conduit close to the pump. Alternatively, if the spigot is opened to prevent development of pressure which would resist fluid flow, a portion of the surging fluid escapes through the spigot.
U.S. Pat. Nos. 2,092,257 Lewis; 2,906,435 Nichols; and 3,441,034 Burks employ pumps to provide the necessary surging of cleaning fluid. Similarly, U.S. Pat. Nos. 2,458,230 Warcup and 2,645,379 Audia appear to rely upon fluid pressure and/or air pressure to achieve cleaning fluid motion. In Lewis, fluid motion is assisted by the necessity of connecting neighboring keg lead lines together, forming a loop. A number of the subsequent devices include manually-operated valves adjacent the keg or the spigot. None of the devices can be expected to operate upon automatic initiation or with a convenience approaching that of the present invention. The invention can be operated entirely without human intervention. The individual kegs need not be disconnected in order to clean the conduit, thereby risking a spill. The kegs are isolated automatically upon operation of the cleaning system and the contents of the conduits are drained under control. The invention further allows so-called lead lines between the kegs and the conduit cleaning system to be safely and conveniently cleaned, for example when replacing an empty keg with a full one. The lead line need only be momentarily connected across fittings provided for that purpose, and flushed. The only manual intervention which is therefore required by the system of the invention is the inescapable need for replacing empty kegs with full ones. The result is a conduit system which is automatically cleaned during off-hours, and which is as clean as practicable from the keg to the spigot.